Production method of polishing composition

ABSTRACT

[Problems to Be Solved] To provide a method for obtaining a polishing composition by which a polishing speed is high and the polished surface has little surface failure. [Means to Solve the Problems] The present invention relates to a production method of a polishing composition containing zirconia oxide sol including: baking at a temperature ranging from 400 to 1000° C., a zirconium compound having d50 (where d50 represents a particle diameter meaning that the number of particles having this particle diameter or less is 50% of the total number of particles) of zirconium compound particles of 5 to 25 μm and d99 (where d99 represents a particle diameter meaning that the number of particles having this particle diameter or less is 99% of the total number of particles) of zirconium compound particles of 60 μm or less, wherein d50 and d99 are measured by measuring a slurry of the zirconium compound by a laser diffractometry; and wet-grinding a powder of zirconium oxide obtained in the above baking in an aqueous medium until d50 of zirconium oxide particles becomes 80 to 150 nm and d99 of zirconium oxide particles becomes 150 to 500 nm, wherein d50 and d99 are measured by measuring the slurry of the zirconium compound by a laser diffractometry. [Selected Drawings]None.

TECHNICAL FIELD

The present invention relates to a production method of a polishingcomposition containing a zirconium oxide sol obtained by a method inwhich a zirconium compound, such as a zirconium carbonate and a hydratethereof is baked and wet-ground, and a production method of asemiconductor device using the polishing composition obtained by theabove production method.

BACKGROUND ART

There are disclosed an aqueous sol of zirconium oxide obtained by amethod including: baking colloidal zirconium oxide having a specificsurface area of 10 to 400 m²/g and a particle diameter (measured by adynamic light scattering method) of 20 to 500 nm and containingdewaterable moisture of 4 to 15% by weight, at a temperature of 400 to1000° C. for 0.05 to 50 hours; adding to the zirconium oxide obtained bythe baking, a water-soluble acid or a water-soluble alkali; andwet-grinding the resultant zirconium oxide; wherein the particlediameter (measured by a dynamic light scattering method) of the obtainedaqueous sol of zirconium oxide is one to three times the particlediameter of the colloidal zirconium oxide before the baking, and aproduction method thereof (Patent Document 1).

Also, there is disclosed a polishing agent containing zirconia and apoly acid such as a polyacrylic acid (Patent Documents 2 and 3).

Also, there is known a method including: neutralizing an aqueoussolution containing a water-soluble zirconium salt such as zirconiumnitrate, zirconium sulfate and zirconium oxychloride with ammonia waterto precipitate zirconium hydroxide; filtrating and washing with waterthe obtained precipitate; and dying and calcining the precipitate, or amethod including: heat-hydrolyzing an aqueous solution of awater-soluble zirconium salt to generate a sot; and drying and calciningthe sol (Non-Patent Document 1).

Further, there is known a method including: heat-hydrolyzing an aqueoussolution of a water-soluble zirconium salt to generate a sol; and dryingand calcining the sol (Non-Patent Document 2).

-   [Patent Document 1] JP-A 8-59242 (Clams and Examples)-   [Patent Document 2] JP-B 3130279 (Claims)-   [Patent Document 3] P-B 3278532 (Claims)-   [Non-Patent Document 1] Ceramics Bifummatsu Gihjutsu (Ceramics Fine    Particles Technology), edited by the Editorial Board of New-ceras    Series, pp. 145-153, published by Gakkensha Co., Ltd., 1994-   [Non-Patent Document 2] Inorganic Chemistry (Inorg. Chem.), Third    Edition, p. 146, 1964

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

An aqueous slurry of an inorganic oxide in which an inorganic oxide suchas silicon oxide and aluminum oxide is dispersed is used as an abrasivegrain of a polishing agent for a chemical mechanical polishing toplanarize a substrate having an uneven surface in a production processof a semiconductor device. However, recently, a polishing agent causingno disadvantage of a surface failure such as a scratch and a polishedsurface having high flatness and high quality can be obtained isvigorously required.

With respect to an aqueous slurry in which zirconium oxide particles aredispersed, various production methods are disclosed, however, there is adisadvantage wherein such conventional methods have complicatedproduction processes and low productivity. Further, when a zirconiumcompound is baked to obtain zirconium oxide, generally the baking isperformed by charging a ceramics container (sagger) filled with a rawmaterial into an electric furnace or a baking gas furnace having acapacity of 0.5 m³ or more, however, the larger the baking furnace is,the more difficult the homogeneous baking of a zirconium compound is dueto a temperature distribution caused in the furnace.

In the present invention, a zirconium oxide sol is obtained by a methodin which a zirconium oxide powder obtained by baking a zirconiumcompound is wet-ground in an aqueous medium, however, depending on thetype, the baking method, the grinding method or the like of thezirconium compound as a raw material, the properties of the obtainedzirconium oxide sol are varied largely. An object of the presentinvention is to provide, in a case when applied to chemical mechanicalpolishing (CMP) in a production method of a semiconductor device, amethod for obtaining a polishing composition containing a zirconiumoxide sol by which a polishing rate, particularly a polishing rate of acopper film is high and a surface failure of a polished surface iscaused seldom.

Means for Solving Problems

The present invention relates to the following aspects:

-   -   as a first aspect, a production method of a polishing        composition containing zirconium oxide sol comprising the steps:        baking at a temperature ranging from 400 to 1000° C., a        zirconium compound having d50 (where d50 represents a particle        diameter meaning that the number of particles having this        particle diameter or less is 50% of the total number of        particles) of zirconium compound particles of 5 to 25 μm and d99        (where d99 represents a particle diameter meaning that the        number of particles having this particle diameter or less is 99%        of the total number of particles) of zirconium compound        particles of 60 μm or less, wherein d50 and d99 are measured by        measuring a slurry of the zirconium compound by a laser        diffractometry; and wet-grinding a powder of zirconium oxide        obtained in the above baking in an aqueous medium until d50 of        zirconium oxide particles becomes 80 to 150 nm and d99 of        zirconium oxide particles becomes 150 to 500 nm, wherein d50 and        d99 are measured by measuring a slurry of the zirconium compound        by a laser diffractometry;    -   as a second aspect, the production method according to the first        aspect, wherein the zirconium compound is a zirconium carbonate        or a hydrate thereof;    -   as a third aspect, the production method according to the first        or second aspect, wherein the balking includes: first baking in        which the temperature is elevated from room temperature with a        temperature elevating rate of 0.1 to 5° C./min until the        temperature reaches a baking temperature of the first baking        ranging from 200 to less than 400° C.; and second baking in        which the temperature is elevated from the baking temperature of        the first baking with a temperature elevating rate of 0.1 to 10°        C./min until the temperature reaches a baking temperature of the        second baking ranging from 400 to 1000° C.;    -   as a fourth aspect, the production method according to the third        aspect, wherein the baking is performed in such a manner that        the second baking is performed immediately after the temperature        has reached the baking temperature of the first baking, or the        second baking is performed after the temperature has been        maintained at the baking temperature of the first baking for        within 100 hours;    -   as a fifth aspect, the production method according to any one of        the first to fourth aspects, wherein the wet-grinding is        performed by grinding a zirconium oxide powder in an aqueous        median by using stabilized zirconia grinding beads having a        diameter of 0.1 to 3.0 mm in a volume ratio of (the zirconium        oxide slurry):(the grinding beads) of 1:0.5 to 2.0 using a        noncontiguous-type grinding apparatus;    -   as a sixth aspect, the production method according to any one of        the first to fourth aspects, wherein the wet-grinding is        performed by grinding a zirconium oxide powder in an aqueous        medium by using a continuous-type grinding apparatus equipped        with stabile zirconia grinding beads having a diameter of 0.03        to 1 mm, a stirring blade having a peripheral-speed of 1 to 15        m/sec and a grinding container under conditions where an        introducing speed of the zirconium oxide slurry into the        grinding container is (V/4 to V) L/min relative to a volume V of        the grinding container and a volume ratio of (the zirconium        oxide slurry):(the grinding beads) is 1:0-5 to 0.9 in the        grinding container;    -   as a seventh aspect, a production method of a semiconductor        device in which a polishing composition obtained by the method        according to any one of the first to sixth aspects is used in        planarization of a substrate having an uneven surface; and    -   as an eighth aspect, the production method of a semiconductor        device according to the seventh aspect, wherein the uneven        surface is an uneven surface formed with a copper or copper        alloy film.

Effects of the Invention

A zirconium oxide sol produced from the zirconium oxide powder accordingto some aspects of the present invention is used as a polishing agentand is used as a polishing agent for a chemical mechanical polishing ina process for planarizing a substrate having an uneven surface in aproduction process of a semiconductor device. For example, the zirconiumoxide sol produced from the zirconium oxide powder according to someaspects of the present invention is useful as (1) a polishing agent fora substrate having an uneven surface formed of copper or copper alloyfilm as a surface to be polished, (2) a polishing agent for polishing aTa or TEN film formed for the purpose of preventing the diffusion ofcopper on an insulating film exposed after the planarization of theuneven surface formed of copper or copper alloy, and (3) a polishingagent for planarizing a substrate having an uneven surface formedcontaining an interlayer insulating film, a low-dielectric constant filmand an insulating film for the trench separation as a surface to bepolished. Also, the zirconium oxide sol according to some aspects of thepresent invention is useful also as (4) a polishing agent for a quartzcrystal containing mainly silica, a quartz glass for a photo mask, aglass hard disc substrate and the like.

BEST MODES FOR CARRYING OUT THE INVENTION

The present invention is a production method of a polishing compositioncontaining zirconium oxide sol including:

baking at a temperature ranging from 400 to 1000° C., a zirconiumcompound having d50 (where d50 represents a particle diameter meaningthat the number of particles having this particle diameter or less is50% of the total number of particles) of zirconium compound particles of5 to 25 μm and d99 (where d99 represents a particle diameter meaningthat the number of particles having this particle diameter or less is99% of the total number of particles) of zirconium compound particles of60 μm or less, wherein d50 and d99 are measured by measuring a slurry ofthe zirconium compound by a laser diffractometry; and

wet-grinding a powder of zirconium oxide obtained in the above baking inan aqueous medium until d50 of zirconium oxide particles becomes 80 to150 nm and d99 of zirconium oxide particles becomes 150 to 500 nm,wherein d50 and d99 are measured by measuring a slurry of the zirconiumcompound by a laser diffractometry.

A zirconium compound used in the present invention is a zirconiumcarbonate or a hydrate thereof and for example, a zirconium carbonate,such as zirconium carbonate (Zr(CO₃)₂), basic zirconium carbonate(ZrCO₄.ZrO₂.8H₂O), and zirconium oxycarbonate (ZrO(CO₃)) is preferablyused.

In the present invention, these zirconium carbonates are used in thefollowing baking, however, as these zirconium carbonates, a zirconiumcarbonate obtained via a zirconium salt can be also used. In the presentinvention, a zirconium carbonate obtained by, for example a method inwhich basic zirconium carbonate obtained as a precipitation by addingsodium carbonate to an aqueous solution of a zirconium salt such aszirconium oxychloride (ZrOCl₂) and zirconium oxynitrate (ZrO(NO₃)₂.2H₂O)is used, a method in which oxyzirconium carbonate obtained byintroducing carbon dioxide into an aqueous solution of zirconiumhydroxide (Zr(OH)₄) obtained by hydrolyzing zirconium nitrate (Zr(NO₃)₄)is used, and a method in which zirconium oxycarbonate obtained byintroducing carbon dioxide into an aqueous solution of a mixture ofzirconium nitrate and ammonium carbonate, can be used. The total contentof an alkali metal element or an alkaline earth metal element containedas impurities in a zirconium carbonate or a hydrate thereof ispreferably less than 1% by weight, based on the weight of the finallyobtained zirconium oxide and it is preferred to render the content ofthe impurities within the above range by water-washing a zirconiumcarbonate or a hydrate thereof to remove the impurities. The zirconiumcarbonate or the hydrate thereof is a water-insoluble powder.

In the present invention, a zirconium compound such as a zirconiumcarbonate and a hydrate thereof is characterized by the particlediameter distribution thereof. With respect to the zirconium compound, azirconium compound from which a slurry in which particles of thezirconium compound have d50 of 5 to 25 μm and d99 of 60 μm or less,wherein d50 and d99 are measured by a laser diffractometry, is obtainedby dispersing the zirconium compound in an aqueous medium, is used as araw material.

In the specification, d50 represents a particle diameter meaning thatthe number of particles having this particle diameter or less is 50% ofthe total number of particles, and d99 represents a particle diametermeaning that the number of particles having this particle diameter orless is 99% of the total number of particles. The d50 represents a valueof an average secondary particle diameter.

In the laser diffractometry, the measurement is performed, for exampleusing an apparatus such as Mastersizer (trade name; manufactured byMalvern Instruments Ltd.) and a particle diameter of particles in aslurry or a sol is measured. When particles are agglomerated with oradhered to each other, a particle diameter of the agglomerated particlesis measured. By a dynamic light scattering method, also a particlediameter of particles in a slurry or a sol is measured and whenparticles are agglomerated with or adhered to each other, a particlediameter of the agglomerated particles is measured.

On the other band, a particle diameter converted from a specific surfacearea value measured by an adsorption of a nitrogen gas to a driedproduct obtained by drying a slurry or a sol (i.e., a particle diameterconverted from a specific surface area measured by a gas adsorptionmethod) is measured as an average value of particle diameters ofindividual particles.

In the present invention, a zirconium compound such as a zirconiumcarbonate or a hydrate thereof having the above particle diameterdistribution is subjected to a baking treatment. The baking treatmentincludes: first baking in which the temperature is elevated from roomtemperature (usually 20° C.) with a temperature elevating rate of 0.1 to5° C./min until the temperature reaches a baking temperature of thefirst baking ranging from 200 to less than 400° C.; and second baking inwhich the temperature is elevated from the baking temperature of thefirst baking with a temperature elevating rate of 0.1 to 10° C./minuntil the temperature reaches a baking temperature of the second bakingranging from 400 to 1000° C.

The first baking is started from room temperature (usually 20° C.).However, when the baking furnace is used frequently, the temperature isnot lowered to room temperature and the baking can be started from, forexample around 40° C.

The baking is performed by a method in which the second baling isperformed immediately after the temperature has reached the bakingtemperature of the first baking, or by a method in which the secondbaking is performed after the temperature has been maintained at thebaking temperature of the first baking for within 100 hours. When thetemperature is maintained in the first baking, the temperature ismaintained at the baking temperature of the first baking. In the secondbaking, after the temperature has reached the baking temperature of thesecond baking, the temperature is maintained for within 240 hours,preferably for 2 to 48 hours.

The above baking is performed in a baking furnace by charging azirconium compound into a ceramics container (for example, sagger). Asthe baking furnace used in the present invention, a batch-type orcontinuous-type electric furnace and gas baking furnace can be used.Examples of the material of the ceramics container (sagger) includealumina, mullite, mullite cordierite and cordierite.

A zirconium oxide powder obtained by the above baking has a particlediameter converted from a specific surface area measured by a gasadsorption method of 8 to 400 nm, preferably 8 to 200 nm and has a X-raycrystallite diameter calculated by the Debye-Scherrer method from a halfband width of a hkl(111) peak of zirconium oxide measured using a powderX-ray diffractometry apparatus of 6 to 250 nm, preferably 6 to 150 nm.

In the present invention, by dispersing a zirconium oxide powderobtained by the baking in an aqueous medium, an aqueous zirconium oxideslurry is obtained and by wet-grinding the obtained slurry, a zirconiumoxide sol can be produced. The dispersing can be performed using awet-grinding apparatus such as a ball mill, a sand grinder and anAttritor and using an altimizer.

The wet-grinding is performed by a method using a noncontiguous-type(batch-type) grinding apparatus and by a method using a continuous-type(circulation-type) grinding apparatus.

During wet-grinding, the concentration of zirconium oxide in thezirconium oxide slurry is preferably 10 to 60% by weight, morepreferably 20 to 40% by weight. pH of the aqueous zirconium oxide slurrycan be adjusted to 1 to 6 by adding an acidic substance. Examples of theacidic substance include an inorganic acid, such as nitric, sulfuric,hydrochloric and boric acids and an organic acid, such as acetic acid,and additionally thereto, an amino acid such as glycine can besimultaneously added. pH of the aqueous zirconium oxide slurry can beadjusted also to 7 to 12 by adding a basic substance. Examples of thebasic substance include sodium hydroxide, potassium hydroxide,tetramethylammonium hydroxide, ethanol amine, diethanol amine,triethanol amine, N,N-dimethylethanol amine, methylethanol amine,monopropanol amine and ammonia; also a water-soluble alkali silicate,such as ammoniumsilicate and quaternary ammonium silicate; and further awater-soluble alkali carbonate, such as quaternary ammonium carbonate.These compounds can be added to the aqueous zirconium oxide sol obtainedaccording to some aspects of the present invention or can be addedduring wet-grinding.

In the method using a noncontinuous-type (batch-type) grindingapparatus, a zirconium oxide powder in an aqueous medium is wet-groundusing stabilized zirconia grinding beads having a diameter of 0.1 to 3.0mm in a volume ratio of (the zirconium oxide slurry):(the grindingbeads) of 1:0.5 to 2.0. A representative noncontinuous-type (batch-type)grinding apparatus is a ball mill apparatus and when this apparatus isused, the wet-grinding is performed, for example at a peripheral-speedof 15 to 110 m/min for 10 to 100 hours.

In the method using a continuous-type (circulation-type) grindingapparatus, a zirconium oxide powder in an aqueous medium is wet-groundusing a continuous-type grinding apparatus equipped with stabilizedzirconia grinding beads having a diameter of 0.03 to 1 mm, a stirringblade having a peripheral-speed of 1 to 15 m/sec and a grindingcontainer under conditions where an introducing speed of the zirconiumoxide slurry into the grinding container is (V/4 to V) L/min relative toa volume V of the grinding container and a volume ratio of (thezirconium oxide slurry):(the grinding beads) is 1: 0-5 to 0.9 in thegrinding container. The number of the circulation is usually 50 to 500.

By wet-grinding an aqueous zirconium oxide slurry, an aqueous zirconiumoxide sol is obtained. An aqueous zirconium oxide sol has a primaryparticle diameter of zirconium oxide converted from a specific surfacevalue measured by a gas adsorption method of 8 to 80 nm, preferably 10to 60 nm. Further, an aqueous zirconium oxide sol has d50 (averageparticle diameter) of zirconium oxide particles measured by a laserdiffractometry ranging from 80 to 150 nm, preferably form 80 to 130 nmand d99 (99% particle diameter) of zirconium oxide particles calculatedfrom a particle size distribution measured by a laser diffractometry of150 to 500 nm, and docs not contain zirconium oxide particles having aparticle diameter of 1 μm or more, preferably 0.6 μm or more as measuredby a laser diffractometry. In the aqueous zirconium oxide sol obtainedaccording to some aspects of the present invention, the recovery rate ofzirconium oxide in a recovered sol in which sediments are removed bysubjecting an obtained aqueous zirconium oxide sol to a treatment usinga centrifuge at 2000 G for one minute is 95% or more. At this time, evenwhen zirconium oxide particles of the zirconium oxide sol areagglomerated by a centrifugal force to form coarse sediments, thecontent of the formed coarse sediments is 7% by weight or less convertedinto a content of particles having a particle diameter of 1 μm or morein the recovered sediments slurry as measured by a laser diffractometry,and even when a large force is applied to the recovered sol during thepolishing, the recovered sol is an aqueous zirconium oxide sol havingsubstantially stability.

The above treatment using a centrifuge is performed as follows. First,the aqueous zirconium oxide sol obtained according to some aspects ofthe present invention is prepared so as to have a solid content aszirconium oxide of 20%. 36 g of the prepared sol are charged into acentrifuge tube and are subjected to a treatment using a high speedrefrigerated centrifuge (trade name: SRX-201; manufactured by Tomy SeikoCo, Ltd.) at 2000 G for one minute. Thereafter, sediments are removedand an aqueous zirconium oxide sol is recovered to weigh the weightthereof. About 3 g of the recovered sol are charged into a 30 ccporcelain crucible and are dried in a dryer of 110° C. Thereafter, therecovered sol is baked at 800° C. to calculate the solid content ofzirconium oxide and the recovery rate of zirconium oxide after thetreatment. Further, the sediments are redispersed in about 30 g of purewater to measure the particle size distribution thereof using a laserdiffractometry particle size distribution measuring apparatus.

The obtained zirconium oxide sol can be used as it is as a polishingcomposition. However, an additive, such as a water-soluble polymer, ananionic surfactant, a nonionic surfactant, a cationic surfactant such asan amine-based substance and hydrogen peroxide water may be added to thepolishing composition either individually or in combination. Theseadditives may be added in a compound state or solution state thereof toa zirconium oxide sol to prepare the polishing composition.

Examples of the water-soluble polymer include a water-soluble organiccompound containing a carboxyl group or a salt thereof. Thewater-soluble organic compound is a polymer or a low molecular weightcompound having in the molecule thereof, at least one carboxyl group orone salt thereof. Examples of the water-soluble organic compound includea polymer (A-1) containing ammonium acrylate and/or ammonium methacylateand an amino acid or derivatives thereof (A-2) and further include awater-soluble cellulose such as carboxymethyl cellulose, hydroxyethylcellulose, hydroxypropylethyl cellulose and hydroxypropyl cellulose, anddextrin.

(A-1) is an ammonium salt of polymers of acrylic acid or methacrylicacid. These polymers may be prepared as a homopolymer, a copolymer ofacrylic acid and methacrylic acid and a copolymer with otherpolymerizable compounds. Examples of the other polymerizable compound asa component of the copolymer include: a monobasic unsaturated carboxylicacid; such as sorbic acid, crotonic acid and tiglic acid; a dibasicunsaturated carboxylic acid, such as muconic acid, maleic acid, fumaricacid, citraconic acid, measaconic acid and itaconic acid; and acrylicesters. Examples of the acrylic esters include 2-hydroxyethylmethacrylate, 2-hydroxypropyl methacrylate, isobutyl methacrylate,t-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate,stearyl acrylate, 2-ethylhexylcarbitol acrylate, 2-methoxyethylacrylate, butoxyethyl acrylate, ethoxyethoxyethyl acrylate,methoxytriethyleneglycol acrylate, methoxypolyethyleneglycol acrylate,stearyl methacrylate, cyclohexyl methacylate, tetrahydrofurfurylmethacrylate, isobonyl methacrylate, dicyclopentenyl acrylate, benzylacrylate, phenylglycidyletherepoxy acrylate, phenoxyethyl methacrylate,phenoxypolyediyleneglycol acrylate, nonylphenol ethoxylated acrylate,acryloyloxyethyl phthalate, tribromophenyl acrylate, tribromophenolethoxylated methacrylate, methyl methacrylate, tribromophenylmethacrylate, methacryloyloxy ethylate, methacryloyloxyethyl malate,methacryloyloxyethyl phthalate, polyethyleneglycol methacrylate,potypropyleneglycol metacrylate, N-methylacrylamide,N-dimethylacrylamide, N-dimethylaminoethyl methacrylate,N-dimethylaminopropylacrylamide, glycidyl methacrylate, n-butylmethacrylate, ethyl methacrylate, allyl methacrylate, cetylmethacrylate, pentadecyl methacrylate, methoxypolyethyleneglycolmethacrylate, diethylaminoethyl methacrylate, methacryloyloxyethylsuccinate, hexanediol diacrylate, neopentylglycol diacrylate,triethyleneglycol diacrylate, polyethyleneglycol diacrylate,polypropyleneglycol diacrylate, neopentyl hydroxypivalate ester,pentaerytritol diacrylate monostearate, glycol diacrylate,2-hydroxyethyl met acryloyl phosphate, bisphenol A ethyleneglycol-adductacrylate, bisphenol F ethyleneglycol-adduct acrylate,tricyclodecanemethanol diacrylate, tris-hydroxyethylisocyanulatediacrylate, 2-hydroxy-1-acryloxy-3-methactyloxypropane,trimethylolpropane tiacrylate, trimethylolpropane ethyleueglycol-adducttriacrylate, trimethylolpropane ethyleneglycol-adduct triacrylate,trimethylolpropane propyleneglycol-adduct triacrylate, pentaerythritoltriacrylate, tris-acryloyloxyethyl phosphate,tris-hydroxyethylisocyanulate triacrylate, modified ∈-caprolactonetriacrylate, trimethylolpropanethoxy triacrylate, glycerinpropyleneglycol-adduct tris-acrylate, pentaerythritol tetraacrylate,pentaerythritol ethyleneglycol-adduct tetraacrylate,ditrimethylolpropane tetraacrylate, dipentaerythritolhexa pentaacrylate,dipentaerythritolmonohydroxy pentaacrylate, urethane acrylate, epoxyacrylate, polyester acrylate and unsaturated polyester.

In (A-1) component, the molar ratio between an ammonium carboxylate anda carboxylate ester in the polymer is 100:0 to 80:20.

As (A-1) component, poly (ammonium acrylate) is most preferably used

Examples of (A-2) component include fatty amino acids, aromatic aminoacids. heterocyclic amino acids, salts thereof and amino acid-basedsurfactants.

Examples of the fatty amino acid include: monoamino monocarboxylicacids, such as glycine, alanine, valine, Ieucine and isoleucine;oxyamino acids, such as serine and threonine; amino acids containing ahetero atom, such as cysteine, cystine and methionine; monoaminodicarboxylic acids, such as aspartic acid and glutamic acid; and diaminomonocarboxylic acids, such as lysine and arginine.

Examples of the aromatic amino acid include phenylalanine and tyrosine.

Examples of the heterocyclic amino acid include histidine, tryptophan,proline and oxyproline.

Examples of the salt of these amino acids include ammonium salts, sodiumsalts and potassium salts of the amino acids.

Examples of the amino acid-based surfactant include N-substituted aminoacids and salts thereof, such as N-acyl amino acid and salts thereof.

Examples of the salt include sodium salts (with NaOH), potassium salts(with KOH), salts with triethanolamine and salts with ammonia, such ascoconut oil fatty acid sarcosine triethanolamine, coconut oil fatty acidacylalanine triethanolamine, coconut oil fatty acid glutamic acidtriethanolamine and lauric acid glutamic acid trichanolamine.

Examples of the anionic surfactant include ammonium oleate, ammoniumlaurate, triethanolamine lauryl sulfate and ammoniumpolyoxyethylenelaurylether sulfate.

Examples of the nonionic surfactant include polyoxyethylenelaurylether,polyoxyethylenesorbitan monolaurate, polyoxyethyleneglycol distearateand polyethyleneglycol monostearate.

Examples of the cationic surfactant include: aqueous solutions ofamine-based substances, such as quaternary ammonium hydroxide,ethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine,methylethanolamine, monopropanolamine and benzotriazol; water-solublealkali silicates, such as ammonium silicate and quaternary ammoniumsilicate; and water-soluble alkali carbonates, such as quaternaryammonium carbonates, for example tetramethylammonium carbonate andtetraethylammonium carbonate.

The polishing composition of the present invention contains 0.5 to 10%by weight of zirconium oxide derived from a zirconium oxide sol and theamount of each of the above additives in the polishing composition is0.2 to 300 parts by weight, preferably 1 to 200 parts by weight as asolid content, relative to 100 parts by weight of zirconium oxide.

In the present invention, the first baking is for removing a zirconiumcompound, particularly a zirconium carbonate or another component thanzirconium component in a hydrate of the zirconium carbonate by baking toproduce zirconium oxide or zirconium oxide precursor.

In the present invention, as a raw material, used is a zirconiumcarbonate or a hydrate thereof having d50 of zirconium compoundparticles of 5 to 25 μm and d99 of zirconium compound particles of 60 μmor less, wherein d50 and d99 are measured by measuring a slurry of thezirconium carbonate or a hydrate thereof by a laser diffractometry, andby performing the first baking of the raw material at a moderatetemperature elevating rate, zirconium oxide having an uniform primaryparticle diameter can be produced. Therefore, since among particles ofthe zirconium oxide sol after the following wet-grinding, there is nocoarse large particle, when the zirconium oxide sol is used as apolishing composition, a scratch is not caused on a polished surface.

On the other hand, when a zirconium carbonate or a hydrate thereof whichdoes not satisfy the above particle diameter distribution, particularlya zirconium carbonate or a hydrate thereof containing a lot of largeparticles is used as a raw material, even if the particle diameter ofthe zirconium oxide powder after the baking is the same as that in thecase where a raw material satisfying the above standard is used, duringwet-grinding until a zirconium oxide sol state, the grinding needs totake longer time and as a result, overground products or ungroundproducts are likely to be generated, so that a product quality andproductivity are lowered.

For example, when a zirconium carbonate or a hydrate thereof having d50of 20 μm as a raw material was baked finally to 800° C., a zirconiumoxide powder having a particle diameter converted by BET method of 85 nmafter the baking was obtained and for dispersing the obtained zirconiumoxide powder to the particle diameter of the zirconium oxide solaccording to some aspects of the present invention, the wet-grindingtime needed only 22 hours.

On the other hand, when a zirconium carbonate or a hydrate thereofhaving d50 of 40 μm as a raw material was baked finally to 750° C., azirconium oxide powder having a particle diameter converted by BETmethod of 85 nm after the baking could be also obtained, however, fordispersing the obtained zirconium oxide powder to the particle diameterof the zirconium oxide sol according to some aspects of the presentinvention, the wet-grinding time needed such a longer time as 75 hours.Moreover, the particle diameter distribution of the obtained zirconiumoxide sol contained not only many small diameter particles, but alsocoarse large diameter particles which could not be ground.

Thus, the particle size distribution of a raw material used influenceslargely the quality of the final product.

Further, by maintaining a relatively moderate temperature elevating ratein the first baking, when a zirconium carbonate or a hydrate thereof isconverted into zirconium oxide, it is believed that zirconium oxidehaving a small primary particle diameter is generated. Even when suchzirconium oxide is subjected to the following baking and wet-grinding,there is generated no coarse large particle, so that such zirconiumoxide can be ground to a similar state to that of a primary particlediameter generated in the first baking.

On the other hand, when the first baking is performed with a hightemperature elevating rate, zirconium oxide having a large primaryparticle diameter is likely to be generated and even when thereafter,such zirconium oxide is subjected to the following baking andwet-grinding, in such zirconium oxide, there are present coarse largeparticles. Therefore, even when such a slurry of zirconium oxide issubjected to the wet-grinding further over a long time period, itresults only in overground products or unground products, so that evenwhen such a zirconium oxide sol is used as a polishing composition, apolishing rate is low and a scratch tends to be caused on a polishedsurface.

Thus, in the production method of the polishing composition containingthe zirconium oxide sol according to some aspects of the presentinvention, by combining a particle diameter distribution of a zirconiumcarbonate or a hydrate thereof used in the production of a zirconiumoxide sol, a temperature elevating rate in the first baking, thefollowing second baking and the wet-grinding, a zirconium oxide solsuitable for a polishing composition can be produced.

The polishing composition containing the aqueous zirconium oxide solobtained according to some aspects of the present invention is use in aprocess for planarizing a substrate having an uneven see in a productionprocess of a semiconductor device as a polishing agent for a chemicalmechanical polishing. For example, the polishing composition of thepresent invention is useful as a polishing agent for planarizing asubstrate having an uneven surface formed with a copper (Cu) or copper(Cu)-alloy film and a substrate having an uneven surface as a surface tobe polished which is formed with an interlayer insulating film, a lowdielectric constant film, and an insulating film in a trench separation.Further, the polishing composition of the present invention is usefulalso as a polishing agent for a quartz crystal composed mainly ofsilica, a quartz glass for a photo mask and a glass hard disc substrate.

EXAMPLES

The analysis methods employed in the present invention are as follows.

(1) pH Measurement

pH was measured using a pH meter (trade name: HM-30S; manufactured by Toa DKK Corporation).

(2) Electric Conductivity Measurement

Electric conductivity was measured using an electric conductivity meter(trade name: CM-300; manufactured by To a DKK Corporation).

(3) Measurement of d50 (Average Particle Diameter) by a LaserDiffractometry

Average particle diameter was measured using a laser diffractometryparticle diameter measuring apparatus (trade name: Mastersize 2000;manufactured by Malvern Instruments Ltd.).

(4) Measurement of Particle Diameter (BET Method Converted ParticleDiameter) Converted from a Specific Surface Area Value Measured by a GasAdsorption Method

A specific surface area value of a sample which has been driedbeforehand under a predetermined condition was measured using a nitrogenadsorption method specific surface area meter (trade name: MonosorbMS-16 type; manufactured by Quntachrome Corporation). Then, BET methodconverted particle diameter was calculated using the measured value ofspecific surface area and the following Equation (1):BET method converted particle diameter (nm)=6000/(d×A)  (1)

-   -   wherein d: specific gravity of zirconium oxide=5.5 g/cm³        -   A: BET specific surface area (m²/g).            (5) Measurement of Powder X-Ray Diffractometry

Using a powder X-ray diffractometry apparatus (manufactured by ShimadzuCorporation), a compound obtained by baiting was determined. Further, ahalf value width of an hkl (111) peak of zirconium oxide was measured toobtain an X-ray crystallite diameter by the Debye-Scherrer method.

(6) Measurement of Average Particle Diameter by Dynamic Light ScatteringMethod

Using a dynamic light scattering method particle diameter measuringapparatus (trade name: DLS6000; manufactured by Otsuka Electronics Co.,Ltd), an average particle diameter was measured

(7) Measurement of Film Thickness of Copper Film

Using a sheet resistance measuring apparatus (trade name: VR-120S;manufactured by Kokusai Denki Alpha Co., Ltd,), a sheet resistance of acopper film was measured and from the obtained value. Then, a copperfilm thickness was calculated, using Equation (2):Copper film thickness=Copper resistivity ρ(Ω-cm)/Sheet resistance ρs(Ω/sq)  (2)

(where Copper resistivity ρ=0.0000017 (Ω-cm)).

(8) Observation of Copper Film Surface

Using a surface observing apparatus 3D digital fine scope (trade name:VC4500; manufactured by Omron Corporation), a copper film surface wasobserved.

(9) Centrifuge

High speed refrigerated centrifuge (trade name: SRX-201; manufactured byTomy Seiko Co., Ltd.)

Example 1

2800 g of zirconium oxycarbonate hydrate (which had a content of 39.0%by weight as ZrO₂) having an average particle diameter d50 measured by alaser diffractometry of 18.5 μm and having a 99% particle diameter d99calculated from a particle size distribution measured by a laserdiffractometry of 47.7 μM was charged into a mullite ceramics containerand the container was capped with a heat resistant plate, followed bybaking the content of the container in 72 L electric furnace. At thistime, the baking temperature was elevated from room temperature to 350°C. at a temperature elevating rate of 1° C./m and was maintained at 350°C. for 5 hours. Further continuously, the baking temperature waselevated at a temperature elevating rate of 2° C./min to 500° C., wasmaintained at 500° C. for 10 hours and was cooled down naturally.Thereafter, the ceramics container was taken out of the electric furnaceto thereby obtain 1093 g of a zirconium oxide powder. The powder wasdetermined with an X-ray diffractometry apparatus and it was found thatthe peak of the powder was identified with the characteristic peak ofzirconium oxide and the X-ray crystallite diameter thereof was 17.5 nm.Further, the powder had a specific surface area measured by a gasadsorption method of 44.7 m²/g and a particle diameter calculatedapproximately from the specific surface area (hereinafter, referred toas BET method converted particle diameter) of 24.4 nm.

Into a ball mill apparatus having a polyethylene cylindrical containerof radius 70 mm×length 220 mm, 3800 g of partially stabilized zirconiabeads having 1 mmφ were charged. With the beads, 369 g of a zirconiumoxide powder, 746 g of pure water and 5.4 g of a 10% nitric acidsolution were mixed to prepare a zirconium oxide slurry in the ball millapparatus. The volume ratio of (Zirconium oxide slurry):(Beads) was1:0.8.

By rotating the cylindrical container at 60 rpm for 24 hours, thezirconium oxide slurry was ground. By water-pushing washing the mixtureof the slurry and the beads with pure water, the slurry was separatedfrom the beads and thereafter an aqueous zirconium oxide sol (a-1)having a zirconium oxide concentration of 23.3% by weight, pH of 5.8 andan electric conductivity of 115 μS/cm was obtained. A powder obtained bydrying the sol at 300° C. had a BET method converted particle diameterof 19.4 nm. Further, the powder had an average particle diameter d50measured by a laser diffractometry of 109 μm and d99 of 234 nm andcontained no zirconium oxide particle having a particle diameter of 0.6μm or more. Further, the aqueous zirconium oxide sol had an averageparticle diameter measured by a dynamic light scattering method of 150nm.

The obtained aqueous zirconium oxide sol was subjected to a treatmentusing a centrifuge at 2000 G for one minute. A recovered sol obtainedafter removing sediments had a recovery rate of zirconium oxide of98.7%. Further, the recovered sediments slurry had a content ofparticles of 1 μm or more measured by a laser diffractometry of 6.3%.

Into an aqueous solution continuing glycine having a concentration of0.12 mol/L, hydrogen peroxide water having a concentration of 0.44 mol/Land benzotriazol having a concentration of 0.001 mol/L, the abovezirconium oxide sol was added so that a concentration of zirconium oxidebecame 5.3% by weight in the mixed solution to thereby prepare apolishing composition.

Example 2

2800 g of zirconium oxycarbonate hydrate (which had a content of 39.8%by weight as ZrO₂) having an average particle diameter d50 measured by alaser diffractometry of 16.8 μm and having a 99% particle diameter d99calculated from a particle size distribution measured by a laserdiffractometry of 36.3 μm was charged into a mullite ceramics containerand the container was capped with a heat resistant plate, followed bybaking the content of the container in 72 L electric furnace. At thistime, the baking temperature was elevated from room temperature to 350°C. at a temperature elevating rate of 1° C. min and was maintained at350° C. for 5 hours. Further continuously, the baking temperature waselevated at 2,C/min to 750° C., was maintained at 750° C. for 10 hoursand was cooled down naturally. Thereafter, the ceramics container wastaken out of the electric furnace to thereby obtain 1114 g of azirconium oxide powder. The powder was determined with an X-raydiffractometry apparatus and it was found that the peak of the powderwas identified with the characteristic peak of zirconium oxide and theX-ray crystallite diameter thereof was 53.9 nm. Further, the powder hada BET method converted particle diameter of 82.7 nm.

Into a ball mill apparatus having a polyethylene cylindrical containerof radius 70 mm×length 220 mm, 3800 g of partially stabilized zirconiabeads having 1 mmφ were charged. With the beads, 369 g of a zirconiumoxide powder, 746 g of pure water and 3.7 g of a 10% nitric acidsolution were mixed to prepare a zirconium oxide slurry in the ball millapparatus. The volume ratio of (Zirconium oxide slurry):(Beads) was1:0.8.

By rotating the cylindrical container at 60 rpm for 24 hours, thezirconium oxide slurry was ground. By water-pushing washing the mixtureof the slurry and the beads with pure water, the slurry was separatedfrom the beads and thereafter an aqueous zirconium oxide sol (b-1)having a zirconium oxide concentration of 24.9% by weight, pH of 4.5 andan electric conductivity of 67 μS/cm was obtained. A powder obtained bydrying the sot at 300° C. had a BET method converted particle diameterof 47.3 nm. Further, the powder had an average particle diameter d50measured by a laser diffractometry of 105 nm and d99 of 240 nm andcontained no zirconium oxide particle having a particle diameter of 0.6μm or more. Further, the aqueous zirconium oxide sol had an averageparticle diameter measured by a dynamic light scattering method of 151nm.

The obtained aqueous zirconium oxide sot was subjected to a treatmentusing a centrifuge at 2000 G for one minute. A recovered sol obtainedafter removing sediments had a recovery rate of zirconium oxide of98.3%. Further, the recovered sediments slurry bad a content ofparticles of 1 μm or more measured by a laser diffractometry of 2.5%.

Into an aqueous solution containing glycine having a concentration of0.12 mol/L, hydrogen peroxide water having a concentration of 0.44 mol/Land benzotriazol having a concentration of 0.001 mol/L, the abovezirconium oxide sol was added so that a concentration of zirconium oxidebecame 5.3% by weight in the mixed solution to thereby prepare apolishing composition.

Example 3

2800 g of zirconium oxycarbonate hydrate (which had a content of 39.8%by weight as ZrO₂) having an average particle diameter d50 measured by alaser diffractometry of 16.8 μm and having a 99% particle diameter d99calculated from a particle size distribution measured by a laserdiffractometry of 36.3 μm was charged into a mullite ceramics containerand the container was capped with a heat resistant plate, followed bybaking the content of the container in 72 L electric furnace. At thistime, the baking temperature was elevated from room temperature to 350°C. at a temperature elevating rate of 1° C./min and was maintained at350° C. for 5 hours. Further continuously, the baling temperature waselevated at 2° C./min to 900° C., was maintained at 900° C. for 10 hoursand was cooled down naturally. Thereafter, the ceramics container wastaken out of the electric furnace to thereby obtain 1114 g of azirconium oxide powder. The powder was determined with an X-raydiffractometry apparatus and it was found that the peak of the powderwas identified with the characteristic peak of zirconium oxide and theX-ray crystallite diameter thereof was 114 nm. Further, the powder had aBET method converted particle diameter of 186 nm.

Into a ball mill apparatus having a polyethylene cylindrical containerof radius 70 mm×length 220 mm, 3800 g of partially stabilized zirconiabeads having 1 mmφ were charged. With the beads, 369 g of a zirconiumoxide powder, 746 g of pure water and 3.7 g of a 10% nitric acidsolution were mixed to prepare a zirconium oxide slurry in the ball millapparatus. The volume ratio of (Zirconium oxide slurry):(Beads) was1:0.8.

By rotating the cylindrical container at 60 rpm for 45 hours, thezirconium oxide slurry was ground. By water-pushing washing the mixtureof the slurry and the beads with pure water, the slurry was separatedfrom the beads and thereafter an aqueous zirconium oxide sol (c-1)having a zirconium oxide concentration of 23.8% by weight, pH of 4.6 andan electric conductivity of 45 μS/cm was obtained. A powder obtained bydrying the sol at 300° C. had a BET method converted particle diameterof 58.7 nm. Further, the powder had an average particle diameter d50measured by a laser diffractometry of 112 nm and d99 of 262 nm andcontained no zirconium oxide particle having a particle diameter of 0.6Sun or more. Further, the aqueous zirconium oxide sol had an averageparticle diameter measured by a dynamic light scattering method of 171nm.

The obtained aqueous zirconium oxide sol was subjected to a treatmentusing a centrifuge at 2000 G for one minute. A recovered sol obtainedafter removing sediments had a recovery rate of zirconium oxide of96.0%. Further, the recovered sediments slurry had a content ofparticles of 1 μm or more measured by a laser diffractometry of 0.3%.

Into an aqueous solution containing glycine having a concentration of0.12 mol/L, hydrogen peroxide water having a concentration of 0.44 mol/Land benzotriazol having a concentration of 0.001 mol/L, the abovezirconium oxide sol was added so that a concentration of zirconium oxidebecame 5.3% by weight in the mixed solution to thereby prepare apolishing composition.

Example 4

2800 g of zirconium oxycarbonate hydrate (which had a content of 39.9%by weight as ZrO₂) having an average particle diameter d50 measured by alaser diffractometry of 19.3 μm and having a 99% particle diameter d99calculated from a particle size distribution measured by a laserdiffractometry of 45.7 μm was charged into a mullite ceramics containerand the container was capped with a heat resistant plate. Sixty-fourpieces of a ceramics container into which zirconium oxycarbonate hydratewas charged was baked in an electric furnace having a furnace capacityof 1 m³. At this time, the baling temperature was elevated from roomtemperature to 350° C. at a temperature elevating rate of 0.5° C./minand was maintained at 350° C. for 5 hours. Further continuously, thebaking temperature was elevated at 2° C./min to 530° C., was maintainedat 530° C. for 10 hours and was cooled down naturally. Thereafter, theceramics container was taken out of the electric furnace to therebyobtain 72 kg of a zirconium oxide powder. The powder was determined withan X-ray diffractometry apparatus and it was found that the peak of thepowder was identified with the characteristic peak of zirconium oxideand the X-ray crystallite diameter thereof was 26.0 nm. Further, thepowder had a BET method converted particle diameter of 36.1 nm.

Into a ball mill apparatus having a polyethylene cylindrical containerof radius 70 mm×length 220 mm, 3800 g of partially stabilized zirconiabeads having 0.5 mmφ were charged. With the beads, 369 g of a zirconiumoxide powder, 739 g of pure water and 10.8 g of a 10% nitric acidsolution were mixed to prepare a zirconium oxide slurry in the ball millapparatus. The volume ratio of (Zirconium oxide slurry):(Beads) was1:0.8.

By rotating the cylindrical container at 60 rpm for 40 hours, thezirconium oxide slurry was ground. By water-pushing washing the mixtureof the slurry and the beads with pure water, the slurry was separatedfrom the beads and Thereafter an aqueous zirconium oxide sol (d-1)having a zirconium oxide concentration of 23.3% by weight, pH of 3.9 andan electric conductivity of 209 μS/cm was obtained. A powder obtained bydrying the sol at 300° C. had a BET method converted particle diameterof 28.9 nm. Further, the powder had an average particle diameter d50measured by a laser diffractometry of 92 nm and d99 of 177 nm andcontained no zirconium oxide particle having a particle diameter of 0.6μm or more. Further, the aqueous zirconium oxide sot had an averageparticle diameter measured by a dynamic tight scattering method of 80nm.

The obtained aqueous zirconium oxide sot was subjected to a treatmentusing a centrifuge at 2000 G for one minute. A recovered sot obtainedafter removing sediments had a recovery rate of zirconium oxide of99.6%. Further, the recovered sediments slurry contained no particle of1 μm or more measured by a laser diffractometry.

Into an aqueous solution containing glycine having a concentration of0.12 mol/L, hydrogen peroxide water having a concentration of 0.44 mol/Land benzotriazol having a concentration of 0.001 mol/L, the abovezirconium oxide sot was added so that a concentration of zirconium oxidebecame 5.3% by weight in the mixed solution to thereby prepare apolishing composition.

Comparative Example 1

3000 g of zirconium oxycarbonate hydrate (which had a content of 40.5%by weight as ZrO₂) having an average particle diameter d50 measured by alaser diffractometry of 39.8 μm and having a 99% particle diameter d99calculated from a particle size distribution measured by a laserdiffractometry of 80.3 μm was charged into a mullite ceramics containerand the container was capped with a heat resistant plate, followed bybaking the content of the container in 72 L electric furnace. At thistime, the baking temperature was elevated from room temperature to 350°C. at a temperature elevating rate of 0.5° C./min and was maintained at350° C. for 5 hours. Further continuously, the baking temperature waselevated at 2° C./min to 700° C., was maintained at 700° C. for 10 hoursand was cooled down naturally. Thereafter, the ceramics container wastaken out of the electric furnace to thereby obtain 1221 g of azirconium oxide powder. The powder was determined with an X-raydiffractometry apparatus and it was found that the peak of the powderwas identified with the characteristic peak of zirconium oxide and theX-ray crystallite diameter thereof was 41.0 nm. Further, the powder hada BET method converted particle diameter of 79.3 nm.

Into a ball mill apparatus having a polyethylene cylindrical containerof radius 70 mm×length 220 mm, 3800 g of partially stabilized zirconiabeads having 1 mmφ were charged. With the beads, 369 g of a zirconiumoxide powder, 746 g of pure water and 5.5 g of a 10% nitric acidsolution were mixed to prepare a zirconium oxide slurry in the ball millapparatus. The volume ratio of (Zirconium oxide slurry):(Beads) was1:0.8.

By rotating the cylindrical container at 60 rpm for 37 hours, thezirconium oxide slurry was ground. By water-pushing washing the mixtureof the slurry and the beads with pure water, the slurry was separatedfrom the beads and thereafter an aqueous zirconium oxide sol (e-1)having a zirconium oxide concentration of 21.5% by weight, pH of 4.9 andan electric conductivity of 64 μS/cm was obtained A powder obtained bydrying the sol at 300° C. had a BET method converted particle diameterof 40.4 nm. Further, the powder had an average particle diameter d50measured by a laser diffractometry of 118 nm and d99 of 26.7 nm andcontained zirconium oxide particle having a particle diameter of 1 μm ormore of 9.3%. Further, the aqueous zirconium oxide sol had an averageparticle diameter measured by a dynamic light scattering method of 145nm.

The obtained aqueous zirconium oxide sol was subjected to a Docent usinga centrifuge at 2000 G for one min. A recovered sol obtained afterremoving sediments had a recovery rate of zirconium oxide of 97.2%.Further, the recovered sediments slurry had a content of particles of 1μm measured by a laser diffractometry of 79.3%.

Into an aqueous solution containing glycine having a concentration of0.12 mol/L, hydrogen peroxide water having a concentration of 0.44 mol/Land benzotriazol having a concentration of 0.001 mol/L, the abovezirconium oxide sol was added so that a concentration of zirconium oxidebecame 5.3% by weight in the mixed solution to thereby prepare apolishing composition.

The polishing using the obtained polishing agent was performed asfollows.

The polishing using the obtained polishing agent was performed using asa polishing cloth, an independently foamed polyurethane resin clothIC-1400 (manufactured by Rodel Nitta Company) and as an object to bepolished, a copper electrolysis metallized film, under conditions wherethe number of rotation of a surface plate was 90 rpm, a polishingpressure was 174 g/cm² and a polishing time was 1 min, using a polishingmachine (manufactured by Techno Rise Corporation).

In Table 1, the evaluation of a polished surface was performed by avisual observation and by a surface observation apparatus, and apolished surface having a failure was evaluated as “bad” and a polishedsurface having no failure at all was evaluated as “good”. The polishingspeed was calculated from film thicknesses of the copper film before andafter the polishing calculated from sheet resistance values of thecopper film before and after the polishing.

TABLE 1 Polishing speed Surface failure Surface (nm/min) of visualobservation Polishing agent copper film observation apparatus Example 1240 good good Example 2 450 good good Example 3 470 good goad Example 4170 good good Comparative 250 bad bad Example 1

By a polishing agent using the aqueous zirconium oxide sol according tosome aspects of the present invention obtained in Examples 1 to 4, thesame or a more polishing speed as or than that by a polishing agentusing the aqueous zirconium oxide sol obtained in Comparative Example 1.Further, from the observation of a polished surface, it was found thatwhile on the polished surface by a polishing agent of ComparativeExample 1, a scratch was caused, on the polished surface by a polishingagent according to some aspects of the present invention obtained inExamples 1 to 4, no scratch was caused.

From the above result of observation, it was demonstrated that theaqueous zirconium oxide according to the present invention is useful asa polishing agent used for a chemical and mechanical polishing.

INDUSTRIAL APPLICABILITY

The polishing composition containing the aqueous zirconium oxide sol ofthe present invention is preferable and suitable as a polishing agentused for a planarization polishing usually referred to as chemicalmechanical polish (CMP) in a semiconductor device production process,and can be applied to polishing a wiring made of a metal, such asaluminum, copper and tungsten. Further, the polishing composition of thepresent invention is preferable and suitable as a polishing agent usedfor an element separation process of a semiconductor device usuallyreferred to as shallow trench isolation (STI), and is preferable andsuitable also as a polishing agent used for polishing a siloxane-based,organic polymer-based, porous material-based, a CVD polymer-based or thelike-based low dielectric constant material for an interlayer insulatingfilm of a semiconductor device. Examples of the siloxane-based materialinclude hydrogenated silsesquioxane, methyl silsesquioxane, andhydrogenated methyl silsesquioxane. Examples of the organicpolymer-based material include a polyarylene ether, a thermalpolymerizable hydrocarbon, a perfluoro hydrocarbon, a polyquinoline, anda fluorinated polyimide. Examples of the porous material include axerogel and a colloidal silica Examples of the CVD polymer include adiamond-like carbon film, a fluorocarbon, an aromatic hydrocarbonpolymer, and a siloxane-based polymer.

Here, a substrate composed mainly of silica is referred to, for examplea quartz crystal, a quartz glass, a glass hard disc, an organic film,low dielectric constant film, interlayer insulating film and CMP fortrench separation in a semiconductor device. Further, the aqueouszirconium oxide sol of the present invention can be applied to polishingan optical crystal material, such as lithium niobate and lithiumtantalate; and a ceramics material, such as aluminum nitride, alumina,ferrite and zirconia.

1. A method of producing a polishing composition containing zirconiumoxide sol, comprising: a first baking of a zirconium compound comprisingzirconium compound particles having a d50 of 5 to 25 μm and a d99 of 60μm or less, wherein the temperature is elevated from room temperaturewith a temperature elevating rate of 0.1 to 5° C./min until thetemperature reaches a first baking temperature in the range of 200 toless than 400° C., a second baking of the zirconium compound, whereinthe temperature is elevated from the first baking temperature with atemperature elevating rate of 0.1 to 10° C./min until the temperaturereaches a second baking temperature in the range of 400 to 1000° C. toobtain a zirconium oxide powder, wherein the second baking is performedimmediately after the temperature has reached the first bakingtemperature, or the second baking is performed after the temperature hasbeen maintained at the first baking temperature for some time, up toabout 100 hours; and wet-grinding the zirconium oxide powder in anaqueous medium until the d50 of zirconium oxide particles becomes 80 to130 nm and the d99 of zirconium oxide particles becomes 150 to 500 nm,wherein the wet-grinding is performed by grinding the zirconium oxidepowder in the aqueous medium by using stabilized zirconia grinding beadshaving a diameter of 0.1 to 3.0 mm in a volume ratio of (the zirconiumoxide slurry):(the grinding beads) of 1:0.5 to 2.0 using anoncontinuous-type grinding apparatus; wherein: d50 and d99 are measuredby measuring a slurry of the zirconium compound by laser diffractometry,and the zirconium compound is a zirconium carbonate or a hydratethereof.
 2. The method of producing a polishing composition containingzirconium oxide sol according to claim 1, further comprising removingsediments with a centrifuge after the wet-grinding.
 3. A method ofproducing a polishing composition containing zirconium oxide sol,comprising: a first baking of a zirconium compound comprising zirconiumcompound particles having a d50 of 5 to 25 μm and a d99 of 60 μm orless, wherein the temperature is elevated from room temperature with atemperature elevating rate of 0.1 to 5° C./min until the temperaturereaches a first baking temperature in the range of 200 to less than 400°C., a second baking of the zirconium compound, wherein the temperatureis elevated from the first baking temperature with a temperatureelevating rate of 0.1 to 10° C./min until the temperature reaches asecond baking temperature in the range of 400 to 1000° C. to obtain azirconium oxide powder, wherein the second baking is performedimmediately after the temperature has reached the first bakingtemperature, or the second baking is performed after the temperature hasbeen maintained at the first baking temperature for some time, up toabout 100 hours; and wet-grinding the zirconium oxide powder in anaqueous medium until the d50 of zirconium oxide particles becomes 80 to130 nm and the d99 of zirconium oxide particles becomes 150 to 500 nm,wherein the wet-grinding is performed by grinding the zirconium oxidepowder in the aqueous medium by using a continuous-type grindingapparatus equipped with stabilized zirconia grinding beads having adiameter of 0.03 to 1 mm, a stirring blade having a peripheral-speed of1 to 15 m/sec and a grinding container under conditions where anintroducing speed of the zirconium oxide slurry into the grindingcontainer is (V/4 to V) L/min relative to a volume V of the grindingcontainer and a volume ratio of (the zirconium oxide slurry):(thegrinding beads) is 1:0.5 to 0.9 in the grinding container, wherein: d50and d99 are measured by measuring a slurry of the zirconium compound bylaser diffractometry, and the zirconium compound is a zirconiumcarbonate or a hydrate thereof.
 4. The method of producing a polishingcomposition containing zirconium oxide sol according to claim 3, furthercomprising removing sediments with a centrifuge after the wet-grinding.